Medizinische Universität Graz - Research portal
Selected Publication:
Kiss, C.
Assessment of brain viscoelasticity in multiple sclerosis using magnetic resonance elastography - an exploratory study
Humanmedizin; [ Diplomarbeit ] Medizinische Universität Graz; 2021. pp. 69
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- Authors Med Uni Graz:
- Advisor:
- Ropele Stefan
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- Abstract:
- Introduction: Magnetic resonance elastography (MRE) is an imaging modality that non-invasively gauges the response of tissue to mechanical excitation. Thereby, it objectively quantifies the viscoelasticity of tissue, which can be altered by pathological processes. In multiple sclerosis (MS), acute inflammation is accompanied by chronic neurodegeneration. However, radiological findings in conventional magnetic resonance imaging (MRI) only poorly reflect these processes and lack correlation with clinical presentation. MRE has already proven sensitivity to subtle alterations in various types of tissue, making it a promising modality to better predict and monitor progression of MS. The purpose of this study was to explore whether MRE can reveal viscoelasticity changes in the in vivo MS brain. It was further evaluated if MRE can contribute to paraclinical assessment of MS patients and to understanding of pathological processes in MS. Methods: In a controlled study, 73 MS patients and 42 healthy volunteers underwent MRI examination. Cerebral MRE was performed using a motion-sensitive stimulated echo sequence (DENSE) with a mechanical excitation at 20 Hertz. Magnitude |G∗| and phase angle φ of the complex shear modulus G∗ were reconstructed by multi-frequency dual-elastico inversion (MDEV). T1- and T2-weighted structural images were acquired for tissue segmentation, brain atrophy estimation and MS lesion analysis. Region of interest-based means in viscoelasticity were compared between cohorts and related to demographic, clinical and radiological characteristics. Results: In the subcortical grey matter of MS patients, according to a multiple regression analysis, age and atrophy correlated with a decrease in φ (p < 0.001). Disease duration was associated with a reduction in |G∗| in white matter (p = 0.01). Disability was not related to viscoelasticity after accounting for age. There was neither a relevant alteration in viscoelasticity in lesions relative to the normal appearing white matter, nor was lesion load associated with brain viscoelasticity. Between cohorts, no difference in brain viscoelasticity was found on tissue level. However, a significant decrease in φ in the thalamus was observed in MS (p = 0.002). Conclusion: MRE can reveal microstructural alterations in the MS brain but lacks sensitivity and specificity to complement clinical assessment to date.